The present invention relates to icing of wind turbines. More particularly, the invention relates to event monitoring or condition monitoring for wind turbines and an event monitoring unit. Specifically, the invention relates to methods for event monitoring for a wind turbine, an event monitoring unit and a computer program product for event monitoring.
In the past, wind turbines experience an increasing demand. Therefore, more and more wind turbines are also planned and erected at sites with conditions that are harsher. As an example, new sites for erecting wind turbines might have a higher probability of icing during the year. Further, the energy output continuously increases and therefore, as an example rotor blade diameters also increase in size. Accordingly, events like icing of rotor blades, fouling of rotor blades, erosion of rotor blades or other parts of the wind turbine, loosening of connection, and/or cracks within a rotor blade may occur. Commonly, such events have often been detected via direct measurements. Great effort has been undertaken in order to allow for more reliable direct measurement results to detect specific events that may occur during operation of a wind turbine. The detection of events like icing, fouling or other disfunctions are important to initialize appropriate countermeasures. As an example, a regulation to shut down the wind turbine in the event of ice-throw might be required.
Additionally, occurrence of events like icing, fouling of rotor blades, cracks in rotor blades or extensive stress of components of the wind turbine may reduce the energy output in the event no counter-measures or appropriate wind turbine control steps are taken.
The detection of the condition of a wind turbine with direct measurements may not result in a sufficient accuracy, since the measurement itself might not be sufficiently accurate or since the signal does not sufficiently correlate to the phenomenon to be detected.